Volatile sulfur compounds, mainly H.sub.2 S and CH.sub.3 SH, generated in the human oral cavity have been documented to be the primary cause of breath malodor. Generally, the presence of these compounds is most noticeable after long periods of reduced saliva flow and abstinence from food or liquids, resulting in the condition known as "morning breath." Breath malodor can also arise after ingesting various foods such as garlic, cabbage and onions.
Zinc compounds, including zinc salts, have been disclosed in the literature as the active ingredient in mouthwashes, rinses and toothpaste to ameliorate breath malodor.
For example, U.S. Pat. No. 4,814,164, discloses a solid oral formulation comprising a zinc compound, an ionone ketone terpene derivative and preferably a mint flavor as the active ingredient.
A clear aqueous composition useful as a mouthwash comprising a zinc compound complexed to an anionic polymer via a carboxylic moiety is disclosed in U.S. Pat. No. 4,992,259.
Other oral compositions containing zinc compounds including toothpastes, mouthwashes, tablets and lozenges, have been disclosed in U.S. Pat. Nos. 4,138,477, 4,325,939, and 4,469,674.